Doou-sps



UNrrED STATES rATENT oFFioE.

THOMAS THORPE, OFWEST CAMBRIDGE, MASSACHUSETTS.

DOOBPSPRING.

Specification of Letters Patent No.l 506, dated December '7, 1837.

To all whom it may concern.' y

Be it known that I, THOMAS THoRPE, of l/Vest Cambridge, county of Middlesex, and State of Massachusetts, have invented a new and useful Improvement in Door-Springs.

The said improvement, the principle thereof, and modes in Whichr I have contemplated the application of the same, to-

' gether With such parts, combinations, or

Characteristics by Which it may be distinguished from other inventions` and Which I claim, I have fully set forth in the follow ing speciication and drawings referred to herein.

A A represents the outer casing of brass, or other suitable metal, shaped as seen in the drawings, or otherwise properly formed.

B is the door on Which the spring is to be fastened; C, the door frame.

E is a metallic rod, turning on a hinge at a, in the side of the piece of metal I", screwed 'to the door frame, The rod E passes through holes in theends b, c of the casing A, moving freely back and forth in said holes.

G is a cross bar, attached to the rod E in a proper manner, and has connected to each extremity the end of a Wound spring, H II, Whose opposite end is confined to the end b of the casing` or to a pin d, passing through the sides thereof.

W hen the door is opened, the springI-I H are extended by the movement o-f the rod E through the slots in the ends b, 0 of the casing, and on withdrawing the force applied to open the door, the springs contract,

and immediately close the same.

Instead of tvvo springs, I may use only one, or I may employ three or more, should y THOMAS THoiiPE. Witnesses R. H. EDDY, A, E. WILSON. 

